Over the past fifteen years, there has been significant research performed in the area of planar antenna design. Initially, this research was directed toward the development of an understanding of the many parameters influencing the operation of planar antennas. Modifications to certain parameters can provide performance improvements in radiation pattern revitalization, increasing gain, shrinking size, increasing bandwidth, or making the antenna structure more compact.
Although many of these topics are still being researched, some emphasis has been placed on making the antenna more compact in recent years. This is because consumer demand has called for electronic components to be smaller in order for electronic devices to be portable and integrated together into a multifunctional device with many features. In the current electronics market, simple devices that perform just one function are rarely seen. As a result, smaller antennas that can be used in multi-function devices are being investigated.